As many as 100,000 demonstrators chased away police to make way for a rally in the centre of Ukraine's capital on Sunday, defying a government ban on protests on Independence Square, in the biggest show of anger about the president's refusal to sign an agreement with the EU.

Chants of "revolution" resounded across a sea of EU and Ukrainian flags on the square. The crowd was by far the largest since the protests began more than a week ago.

Many of the demonstrators had travelled to Kiev from western Ukraine, where pro-EU sentiment is particularly strong.

"We are furious," said Mykola Sapronov, a 62-year-old retired businessman. "The leaders must resign. We want Europe and freedom."

Protests have been held daily in Kiev for more than a week after the president, Viktor Yanukovych, backed away from an agreement that would have established free trade and deepened political co-operation between Ukraine and the EU. He justified the decision by saying that Ukraine could not afford to break trade ties with Russia.

The EU agreement would have been signed on Friday; since then the protests have gained strength.

Sunday's demonstration was further fuelled by anger about the violent dispersal of several hundred protesters at Independence Square early on Saturday. Some of the protesters were bleeding from their heads and arms after riot police beat them with truncheons.

All police left the square as demonstrators approached on Sunday and removed metal barriers blocking it off.